Buffer mechanism



Dec. 30, 1958 c. E. SIMPSON 2,866,389

BUFFER MECHANISM Filed June 4, 1954 2 Shets-Sheet 1 INVENTOR. E111rEncEE 5im :|5m-L flTTOENEYS Dec. 30, 1958 c. E. SIMPSON BUFFER MECHANISM 2 Sheets-Sheet 2.

Filed June 4, 1954 R m m m nrrakivs vs BUFFER MECHANISM Clarence E. Simpson, Wilbraham, Mass., assignor to the United States of America as represented by the Secretary of the Army Application June 4, 1954, Serial No. 444,440

2 Claims. (Cl. 89-198) This invention relates to "buffer devices for resiliently stopping the breech enclosure member of a firearm in recoil position and is particularly adapted to those firearms in which compactnessof construction is desired.

An object of this invention is to provide a recoil bufier for a firearm which is compact and rugged in construction, durable, efficient in operation and easy to manufacture.

Another object of this invention is to provide a recoil buffer device which cushions the recoil blow of the breech enclosure member with little or no counter-recoil thrust thereto.

The specific object of this invention is to provide a buffer mechanism which includes split contractable rings cooperably mounted on split contractable sleeves.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a longitudinal sectional side view of a firearm showing the recoil buffer;

Fig. 2 is similar to Fig. l but showing the recoil buffer actuated by the firearm bolt; and

Fig. 3 is an exploded view of the recoil bufler assembly.

Shown in the figures is a firearm receiver 12 with a bolt 13 mounted therein for slidable longitudinal movement.

Releasably secured to the rear portion of receiver 12, so as to enclose the rear end thereof, is a back plate member 14. Extending rearwardly from back plate member 14 is a buffer housing 15 having therethrough a longitudinally disposed cylindrical bore 16 which communicates with the interior of receiver 12. The rear end of bore 16 is threaded, as noted by 17, and the forward end is reduced in diameter by an annular flange portion 18. Mounted for slidable movement in bore 16 is a buffer 19 having a cylindrical piston portion 20. Piston 20 is provided with a smaller diameter portion 21 which is receivable through fiange 18 into the interior of receiver 12 so as to be contactable by bolt 13. The rear end of piston 20 is recessed, as noted at 22 to form an annular inwardly and forwardly sloping surface 23. Protruding rearwardly from the center of piston 20 is a rod portion 24. Threadably received by threaded portion 17 is a screw member 25 which is provided with an axial hole 26 arranged to slidably receive rod portion 24 therethrough. The forward side of screw member 25 is recessed, as noted at 27 to form an annular, inwardly and rearwardly sloping cam surface 28 provided with a similar degree of inclination as sloping surface 23.

A ring 29 is mounted in bore 16 so that the diameter thereof is parallel with the front side of screw member 25 and the back side of piston 20. Ring 29 is provided with an inverted truncated triangular cross-section the base of which slidably engages the wall of bore 16 and the truncated sides extend angularly thereinto with a similar degree of inclination as that surfaces 23 and 28.

2,866,389 Patented Dec. 30,

Arranged on each side of ring 29 is one of a pair of rings 30 having a cross-section similar to but the reverse of that of ring 29 with the base being concentric with the surface of bore 16 and the sides arranged to mate the adjacent sides of ring 29 and surfaces 23 or 28.

Rings 30 are of split type with the ends spaced resiliently apart. The diameters of rings 30 are approximately that of ring 29, when expanded, and are, of course, smaller when contracted; As one of the sides of rings 30 are cammingly engaged with the adjacent sides of ring 29 and the opposite sides of rings 30 are cammingly engaged with surfaces 23 and 28 when pressure is exerted rearwardly against buffer 19 such camming engagement contracts rings 30. The resistance of rings 30 to the rearward movement of buifer 19 may be varied by adjusting screw member 25.

Arranged longitudinally within rings 29 and 30 is an assembly comprised ofsnugly nested sleeves having graduated diameters. The largest one of such sleeves is noted at 33, the smallest at 31 and the intermediate at 32. Sleeves 33, 32 and 31 have a length slightly less than that of the channel formed by the interiors of rings 29 and 30 when compressed and are split longitudinally with the ends formed thereby spaced resiliently apart. Sleeve 33 is arranged to snugly engage the insides of rings 30 when both are in normal expanded position whereby contraction of rings 30 simultaneously contracts sleeves 33, 32 and 31. Bolt 13 is arranged to be stopped by back plate 14 before the split ends of rings 20 and/or sleeves 31, 32 and 33 engage, if the recoil force of the bolt should at any time overcome the resistance of such rings and sleeves, to prevent damage thereto.

Operation When bolt 13 recoils in receiver 12 and approaches a position to be stopped, it strikes portion 21 of buffer 19 which extends into the receiver through back plate member 14. The blow against buffer 19 causes rings 30 to be contracted to a smaller diameter by the camming cooperation of ring 29, screw member 25 and piston 20, as has already been explained. As sleeve 33 is in engagement with the inside surfaces of rings 30 the contractions thereof contract such sleeve which in turn contracts sleeve 32 which contracts sleeve 31 until the combined accelerated frictional resistance of the rings and sleeves bring the bolt to a resilient stop. It is obvious that during the contractions of such sleeves and rings there is sliding movement between such members and between them and piston 20 and screw 25 with which they are engaged. Because of the force required to contract rings 30 and sleeves 31, 32 and 33 considerable pressure is exerted against the engaged surfaces, producing friction therebetween when moved, which also serves to absorb the energy in the bolt. Furthermore, the frictional engagement of the resiliently engaged surfaces acts to retard the expansion of sleeves 31, 32 and 33 and rings 30 to normal expanded position, so little if any counter-recoil thrust is impartred to bolt 12.

It is obvious from the foregoing that there is here provided a recoil buffer for a firearm which is compact and rugged in construction, durable, eflicient in operation and easy to manufacture.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

- 1. In a firearm having a bolt reciprocable between a battery and a recoil position, a recoil buffer including a compressible resilient means comprised of a plurality of split rings resiliently contractable to smaller diameters when said resilient means is compressed and alternating noncontractable rings, said split and noncontractable rings being aligned to form a cylindrical chamber, cooperating cam means on said split and noncontractable rings for contracting said split rings when said resilient means is compressed and for giving frictional resistance to the compression of said resilient means, means contactable by the bolt before reaching the recoil position for compressing said resilient means, a plurality of contractable split sleeves nested in frictional engagement with each other and housed within said chamber for frictional engagement with the insides of said split rings to frictionally and resiliently resist the contractions thereof.

2. For a firearm having a receiver and a bolt reciprocable therein between a recoil and a battery position, a device for resiliently stopping the recoil flight of the bolt in the recoil position including in combination a housing mounted to the rear end of the receiver and provided with a cylindrical bore longitudinally therethrough communicating with the inside of the receiver, an annular flange provided at the front end of said bore, a buffer including a rod portion and a piston portion slidingly received by said bore and provided with a reduced diameter portion extending forwardly from an annular shoulder formed thereby to be engaged by the bolt when approaching battery position when said flange and shoulder are in contact, a cylindrical member mounted within the rear end of said bore and provided with an axial hole for slidingly receiving said rod portion, an inwardly and forwardly sloping annular surface provided on the rear end of said piston portion, an annular inwardly and rearwardly sloping cam portion provided on the rear end of said cylindrical member, a ring having a substantially triangular cross-section mounted in said bore between said buffer and said cylindrical member, a first split ring disposed between said ring and said piston portion for engagement therewith, a second split ring disposed between said ring and said cylindrical member for engagement therewith, said first and second split rings having a triangular cross-section the reverse of that of said ring whereby said ring and said sloping surface on said piston portion and said cam portion on said clindrical member cooperate to contract said split ring by the rearward movement imparted to said piston portion by the bolt to offer resistance to the rearward movement of the bolt, a contractable cylindrical chamber formed by the insides of said first and second split rings, a nest of contractable split sleeves in resilient and frictional engagement housed in said chamber for resilient and frictional engagement with said first and second split rings to resist the contractions thereof, and thread means provided on said cylindrical member and in said bore where by sail cylindrical member is movable to adjust the resistance of said buffer to rearward movement of the bolt.

References Cited in the file of this patent UNITED STATES PATENTS 812,326 Browning Feb. 13, 1906 2,229,390 Roemer Jan. 21, 1941 2,370,835 Bell et al. Mar. 6, 1945 2,379,461 Simpson July 3, 1945 2,456,652 Simpson Dec. 21, 1948 

